Telomerized triglyceride vegetable oil for lubricant additives

ABSTRACT

There is disclosed a group of lubricant additives that have improved oxidative stability, high viscosity and relatively lower cost and that comprise telomerized vegetable oils having no more than 4% polyunsaturated fatty acids. There is also disclosed sulfurized and phosphite adduct derivatives of telomerized vegetable oil for use as lubricant additives.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of U.S. patent application Ser. No.596,820 filed Oct. 12, 1990 now abandoned.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to lubricant compositions and lubricantadditives comprising telomerized vegetable oil. More specifically, thisinvention relates to telomerized vegetable oil wherein the vegetable oilis a triglyceride having fatty acid side chains predominantly from about16 to about 26 carbon atoms in length and at least one double bond. Thisinvention further relates to methods for using a telomerized vegetableoil in a lubricant additive or a lubricating composition and to methodsfor telomerizing vegetable oil.

BACKGROUND OF THE INVENTION

Lubricants are widely used to reduce friction between surfaces of movingparts and thereby reduce wear and prevent damage to the surfaces andparts. Lubricants are composed principally of a base stock and alubricant additive. The base stock is generally a relatively highmolecular weight hydrocarbon. In applications where there is a largeamount of pressure applied to moving parts, lubricating compositionscomposed only of hydrocarbon base stock tend to fail and the partsbecome damaged. This problem has been addressed by adding materials(i.e., lubricant additives) to the lubricating composition to increasehigh pressure performance. Such additives are called "extreme pressureadditives." Examples of extreme pressure additives are sulfurized spermwhale oil and sulfurized jojoba oil. There is a continuing need in theart to find alternate extreme pressure additives because sperm whale oilis no longer available due to an international ban and jojoba oil isexpensive and in short supply.

Extreme pressure additives prevent destructive metal-to-metal contact inlubrication at high pressure and/or temperature such as that found incertain gear elements in automotive vehicles and various industrialmachines where high pressure can cause a film of lubricant to rupture.Extreme pressure/anti-wear lubricants should have good lubricity, goodcooling properties, high film strength, good load bearing ability, andmiscibility with the usual types of base oils.

To make lubricants, such as motor oils, transmission fluids, gear oils,industrial lubricating oils, metal working oils, etc., one starts with alubricant grade of petroleum oil from a refinery, or a suitablepolymerized petrochemical fluid. Into this "base stock" is blended smallamounts of specialty chemicals that enhance lubricity, inhibit wear andcorrosion of metals, and retard damage to the fluid from heat andoxidation.

Anti-wear agents, extreme pressure agents and friction modifiers havebeen developed that are generally organic or organometallic compoundscontaining halogens, sulfur, phosphorus, or a combination of the three.Halogens have noted low-temperature metal-coating activity but can causeserious corrosion problems at the higher operating temperatures ofmodern vehicles or industrial machinery and have environmental problemsupon disposal. Manufactures have, therefore, switched to derivatives ofsulfur and phosphorus for lubricant additives.

Before 1972, lubricant additives were based on raw and chemicalderivatives of sperm whale oil, a mono-ester of monounsaturated fattyacid chains. Replacement additives include phosphorized lard oils,sulfurized polyisobutylene and moderate molecular weight polymers. Theseadditives have met with limited success. Better lubricating properties(i.e., friction and reduced wear) have been achieved with a natural waxester, such as jojoba oil. Lubricant additives using jojoba oil havebeen described in U.S. Pat. No. 4,873,008, the disclosure of which isincorporated by reference herein. Jojoba oil suffers from limitedavailability and high cost.

Synthetic wax esters can be made by esterifying an unsaturated fattyacid and an unsaturated fatty alcohol. Synthetic wax ester can besulfurized. Sulfurized wax esters often display excellent lubricatingproperties. However, the cost of a process to create and isolate asynthetic wax ester is extremely high and comparable with the cost ofnatural wax ester.

One solution to this problem is described in U. S. Pat. No. 4,970,010,the disclosure of which is incorporated by reference herein. This patentdescribes a group of sulfurized derivatives of triglyceride vegetableoil that achieve acceptable lubricating properties. However, processingcosts are still relatively high because this process requires thepresence of at least 25% wax ester and preferably, 50% wax ester. Forpractical applications, synthetic wax esters have to be derived fromnatural vegetable triglycerides, such as rapeseed oil or corn oil.Cost-adding conversion steps to a synthetic wax ester make synthetic waxesters relatively uneconomical for use as lubricant additives.

Liquid wax esters are formed by forming an ester bond between thefunctional groups of an unsaturated fatty acid and an unsaturated fattyalcohol. Liquid wax esters have been made from triglyceride rapeseedoil, such as a high erucic acid rapeseed (HEAR) oil by a complex andexpensive process, such as is described in Bell, U.S. Pat. No.4,152,278. HEAR oil is a triglyceride in its native form. Synthetic waxester made from HEAR oil is a substitute for sperm whale oil or anatural wax ester, such as jojoba oil.

Synthetic wax esters can be made into phosphorous or sulfurizedderivatives to improve friction, wear and extreme-pressure properties ofa fluid. For example, sulfurized vegetable oil wax esters are describedin U. S. Pat. No. 4,152,278 and phosphite adducts of synthetic vegetableoil wax esters are described in U.S. Pat. No. 4,970,010.

Although the supply of HEAR is more stable than the supply andavailability of jojoba oil, the process of transforming a triglycerideoil into a mono-ester form is a difficult and expensive process withlittle, if any, cost advantage over jojoba oil. Thus, there is a need inthe art to be able to use a vegetable triglyceride oil directly as alubricant additive or as a derivative to eliminate the expensiveconversion steps into a synthetic wax ester and retain the advantage oflow cost and availability.

Triglyceride vegetable oils, such as HEAR, contain 10%-25%polyunsaturated fatty acids and are rich in longer chain (20-24 carbonatom) fatty acids. Dienic (two double bonds) fatty acids and trienic(three double bonds) fatty acids in a triglyceride oil are more reactivethan monoenic (single double bond) fatty acids. Double bonds in avegetable oil triglyceride, when used directly in a high temperatureoxidizing environment, such as a lubricant additive, are attacked byoxygen and heat which causes the triglyceride to darken, thicken andlose solubility within lubricating oil base stocks. These undesirableproperties limit the usefulness of triglyceride vegetable oils forlubricant additives. Therefore, there is a further need in the art tofind an inexpensive processing means to improve the lubricatingproperties and characteristics of triglyceride oils for use as lubricantadditives. This invention was made to satisfy those needs.

SUMMARY OF THE INVENTION

The present invention relates to telomerized triglyceride vegetableoils, sulfurized and phosphorus derivatives of telomerized triglyceridevegetable oils, and combinations thereof for use as lubricant additives,thermal oxidative stability enhancers and viscosity improvers. Theinvention further relates to telomerized triglyceride vegetable oils asa lubricating composition base stock substitute. Further still, thisinvention provides a process to telomerize triglyceride vegetable oils,wherein the telomerized vegetable oils have a lower iodine number thanthe vegetable oil before telomerization, increased viscosity, and nomore than 4% of the fatty acids of the telomerized vegetable oil arepolyunsaturated. The telomerized vegetable oil is further characterizedby having aliphatic rings connecting fatty acids from differenttriglyceride molecules or from the same triglyceride molecule.

The telomerized vegetable oil of the present invention comprises no morethan 4% polyunsaturated fatty acids and is polymerized, having aliphaticrings connecting triglyceride molecules. The telomerized vegetable oilis produced by a process comprising heating a triglyceride vegetable oilin a non-oxidizing atmosphere for at least 5 hours at a temperature offrom about 200° C. to about 400° C. Traces of water in the form of watervapor facilitate the telomerization process and act as a catalyst forthe telomerization reaction. The triglyceride vegetable oil has fromabout 10% to about 75% polyunsaturated fatty acids and fatty acid chainsof from about 16 to about 26 carbon atoms in length. Preferably thevegetable oil is a mixture of a lower polyunsaturated vegetable oil suchas rapeseed oil and a higher polyunsaturated vegetable oil, such as cornoil or safflower oil.

The present invention further comprises phosphite and sulfurizedderivatives of telomerized vegetable oil. A phosphite adduct oftelomerized vegetable oil comprises a mono-, di-, tri-, tetra-, penta-,or hexa-adduct of a reaction product of: ##STR1## and a telomerizedvegetable oil, wherein R is selected from the group consisting of H,C₁₋₁₂ alkyl, C₁₋₁₂ alkaryl, C₁₋₁₂ aralkyl, and cyclo C₄₋₈ alkyl.Preferably, R is selected from the group consisting of H, C₄₋₈ alkyl,C₄₋₈ alkaryl, C₄₋₈ aralkyl, and cyclo C₄₋₈ alkyl. A sulfurizedderivative of telomerized vegetable oil comprises from about 5% to about15% sulfur mixed with telomerized vegetable oil.

Lastly, the present invention comprises lubricant additives andlubricating compositions that comprise at least one component selectedfrom the group consisting of a telomerized vegetable oil as describedherein, a phosphite adduct of telomerized vegetable oil and sulfurizedand telomerized vegetable oil.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a chemical diagram of a telomerized vegetable oil having analiphatic ring and formed by heating in a non-oxidizing atmosphere.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to the discovery that telomerizedvegetable oil comprising aliphatic rings and no more than 4%polyunsaturated fatty acids can be substituted for synthetic and natural(jojoba oil) vegetable wax esters in lubricant additives and lubricatingcompositions. The advantage of telomerized vegetable oils is that theyare relatively inexpensive when compared to synthetic wax esters of thesame vegetable oils because the process of telomerization requires fewerprocessing steps and costs for commercial manufacture. Telomerizedvegetable oil derivatives can also be substituted for wax esterderivatives that are used in lubricant additives. Such derivativesinclude phosphite adducts of telomerized vegetable oil and sulfurizedtelomerized vegetable oil.

The present invention also relates to a telomerized vegetable oilproduced by a process comprising heating a vegetable oil or acombination of vegetable oils to a temperature of 200° C. to 400° C. ina non-oxidizing atmosphere and in the presence of a trace watercatalyst, periodically measuring viscosity of the oil over time as ameasure of the telomerization reaction. The telomerization reaction iscompleted, by one measure, when the rate of viscosity increase over timedecreases and remains constant.

The present invention further relates to a method for improving theviscosity of a lubricant additive comprising adding a telomerizedvegetable oil or a sulfurized or phosphorous derivative thereof in placeof a triglyceride vegetable oil or wax ester thereof. Telomerizedvegetable oils have the surprising property of increasing viscosity ascompared with triglyceride vegetable oils or wax esters when used aspart of a lubricant additive composition or a lubricating composition.The following table compares properties of rapeseed oil (refined anddegummed) with the same rapeseed oil telomerized at 300° C. for tenhours in a nitrogen atmosphere in the presence of water vapor as acatalyst.

                  TABLE 1                                                         ______________________________________                                        Property        Rapeseed Oil                                                                              Telomerized Oil                                   ______________________________________                                        Iodine Number   114          82                                               Viscosity @ 40° C.                                                                     46.45 cps    113.7 cps                                        Viscosity @ 100° C.                                                                    10.93 cps    18.64 cps                                        Viscosity Index 236          184                                              Specific Gravity @ 24° C.                                                              .906         .919                                             Solidification Pt.                                                                            -10° C.                                                                             -4.5° C.                                  Color           light yellow yellow                                           ______________________________________                                    

These data for triglyceride rapeseed oil and telomerized rapeseed oilcompare physical properties of this oil before and after a partialtelomerization reaction. Telomerization was evidenced by a reducediodine number at which approximately 4% of the polyunsaturated fattyacids were unreacted.

During the telomerization reaction, iodine number decreases andviscosity increases linearly with time. Either or both assays areappropriate for measuring telomerization. The following Table 2 shows arate of formation of a telomer after 30 hours heating at 300° C. under anitrogen blanket with water vapor.

                  TABLE 2                                                         ______________________________________                                        Rapeseed Oil         Safflower Oil                                            Pro-                10   20   30             10   30                          perty 0      5 hrs  hrs  hrs  hrs  0    5 hrs                                                                              hrs  hrs                         ______________________________________                                        Iodine                                                                              120    103     92   80   78  140   115  90   54                         No.                                                                           Viscos-                                                                             541    927    1194 1901 3002 530  1090 2020 5125                        ity                                                                           (cs.) @                                                                       40° C.                                                                 ______________________________________                                    

The telomers of both rapeseed oil and safflower oil are viscous,light-colored oils that are soluble in organic solvents and inhydrocarbon oils and esters. Some physical properties are provided inTable 3 for rapeseed oil telomer and safflower oil telomer heated underwet N₂ at 300° C. for 30 hours.

                  TABLE 3                                                         ______________________________________                                                                     Safflower                                        Property    Rapeseed Oil Telomer                                                                           Oil Telomer                                      ______________________________________                                        Iodine No.  78               57                                               Kinematic viscosity                                                           cs @ 40° C.                                                                        301.8            482.9                                            cs @ 100° C.                                                                       38.69            56.41                                            Viscosity index                                                                           181              185                                              Molecular Weight                                                                          2700             3100                                             ______________________________________                                    

In addition to rapeseed oil, other triglyceride vegetable oils can betelomerized by the process described herein to provide a telomerizedvegetable oil. For example, other appropriate vegetable oils includecorn oil, crambe oil, meadowfoam oil, peanut oil, safflower oil, soybeanoil and combinations thereof. The percentages of C₁₈, C₂₀ and C₂₂ fattyacids and the number of double bonds are listed for each vegetable oilin Table 4 below. The relative amounts of saturated, monoene, diene andtriene fatty acids are shown.

                  TABLE 4                                                         ______________________________________                                        Percentages                                                                   C.sub.18        C.sub.20   C.sub.22                                                  mono-            mono-      mono-      Sat.                            Oil    ene     diene    ene   diene                                                                              ene   diene                                                                              acid                            ______________________________________                                        Corn   29      54                             17                              Crambe 62      31                             7                               Meadow-                 62.6       12.3  22.1 3.0                             foam                                                                          Peanut 62.2    20.6     1.0                   16.3                            Rapeseed                                                                             76      11(6)*                         7                               Safflower                                                                            14.4    66.8                           18.8                            Soybean                                                                              21.2    50.6(9.2)*                     19.0                            ______________________________________                                         *triene                                                                  

Table 5 compares the iodine number of each of the triglyceride vegetableoils as starting materials before telomerization and after, 5, 6.5 or7.5 hours of telomerization under conditions of 300° C. in a nitrogenatmosphere with a trace amount of H₂ O. The ionization number decreaseswith the telomerization process.

                  TABLE 5                                                         ______________________________________                                                            Iodine Number                                                    Iodine Number                                                                              After 5, 6.5, or 7.5 Hours                                Oil      Starting Material                                                                            5       6.5     7.5                                   ______________________________________                                        Corn     99.2           67.1    61.6    60.3                                  Carmbe   61.1           60.0    55.9    55.6                                  Meadowfoam                                                                             85.1           71.6    68.5    67.3                                  Peanut   71.2           71.0    70.2                                          Rapeseed 100.9          82.2                                                  Safflower                                                                              115.3          58.7    43.5                                          Soybean  104.7          102.2   101.7   98.9                                  ______________________________________                                    

Table 6 shows that viscosity increases during the course of thepolymerization reaction. Moreover, addition of more polyunsaturatedvegetable oil, such as linseed oil, to a vegetable oil with a lowerconcentration of polyunsaturated fatty acids, such as rapeseed oil,crambe oil or meadowfoam oil, results in an acceleration of thetelomerication reaction. The following table lists viscosity incentistokes at 40° C. at each time.

                                      TABLE 6                                     __________________________________________________________________________                     Reaction                                                     Composition (oil)                                                                              Temp. °C.                                                                    0  1  2  3  4  5   10 30                               __________________________________________________________________________    Rapeseed (200 g) 300   54.1                                                                             -- -- -- -- 92.7                                                                              119.4                                                                            300.2                            Safflower (200 g)                                                                              305   53.0                                                                             -- -- -- -- 109.0                                                                             202.0                                                                            512.5                            Rapeseed (200 g) 320   54.1                                                                             59.0                                                                             67.5                                                                             73.3                                                                              81.5                                                                            92.7                                                                              -- --                               Rapeseed (180 g) + Linseed (20 g)                                                              320   55.1                                                                             69.8                                                                             76.7                                                                             89.3                                                                             103.8                                                                            119.1                                                                             -- 510.7                            Rapeseed (160 g) + Linseed (40 g)                                                              320   51.1                                                                             64.9                                                                             80.5                                                                             94.8                                                                             109.8                                                                            124.9                                                                             -- 515.6                            __________________________________________________________________________

Progressive decrease in iodine number with time is a measure of theextent of telomerization. Similar monitoring of the telomerizationreaction can be made by measuring increasing viscosity or increasingmolecular weight as a measure of polymerization. The iodine numberdecreases because the number of carbon-carbon double bonds decrease withformation of aliphatic rings and, particularly cyclohexane rings betweenfatty acid groups. Most telomerization reactions are completed by 30hours at 300° C. Similarly, viscosity increases as the degree ofpolymerization increases through formation of aliphatic rings.

These data comparing physical properties of several triglyceridevegetable oils versus its telomerized counterpart show a reduced iodinenumber or an increased viscosity at which approximately 4% of thepolyunsaturated fatty acids were unreacted. These data show reducediodine numbers for rapeseed oil, in addition to other vegetable oils,such as crambe oil, corn oil, peanut oil, meadowfoam oil, soybean oil,and safflower oil.

In a preferred embodiment, the starting vegetable oil is a combinationof a triglyceride vegetable oil having a lower polyunsaturated fattyacid content in the about 10% to 25% range (e.g., rapeseed oil,meadowfoam oil, crambe oil) and a triglyceride vegetable oil having ahigher polyunsaturated fatty acid content of more than 50% (e.g., cornoil, linseed oil). Addition of a higher polyunsaturated vegetable oilaccelerates the telomerization reaction, allowing a completion of thereaction (defined as a plateau in a viscosity versus time curve) fasterwith processing and energy cost savings.

Rapeseed oil is a triglyceride vegetable oil containing about 15% to 25%polyunsaturated fatty acids. The degree of unsaturation and percentageof polyunsaturation depends upon crop growing conditions. Thesepolyunsaturates are mainly linoleic and linolenic acids and are thesource of a problem of oxidative instability of vegetable oils. Thetelomerization process heats the vegetable oil from about 200° C. toabout 400° C. in a non-oxidizing atmosphere (preferably a reducingatmosphere, such as nitrogen) in the presence of trace amounts of wateras a catalyst, to cause the polyunsaturated fatty acids to formmonounsaturated polymers containing aliphatic rings. This, in essence,polymerizes the triglycerides without separating the fatty acidcomponent from the glycerol backbone. An example of the reaction productchemical configuration is shown in FIG. 1. The resulting telomerizedvegetable oil displays characteristics of reduced iodine numberreflecting the fact that 4% or less of the fatty acids arepolyunsaturated, the presence of aliphatic rings connecting fatty acidchains of different triglyceride molecules, a significant reduction ofthe viscosity index, and increased oxidative stability.

The process of telomerization of a vegetable oil comprises heating acrude, partially purified or purified vegetable oil at a temperature offrom about 200° C. to about 400° C. from about 6 to about 40 hours in anon-oxidizing atmosphere. Preferably a reducing atmosphere is used witha gas selected from the group consisting of nitrogen, helium, argon,neon, and combinations thereof. Most preferably, a trace amount of wateris added to facilitate the telomerization process. The amount oftelomerization is determined by periodically measuring the iodine numberor viscosity of the vegetable oil, and when the telomerized oil's iodinenumber indicates less than 4% polyunsaturated fatty acids or viscosityincreases at a decreased rate, the telomerization process is complete.Preferably, the iodine number drop indicates less than 2%polyunsaturated fatty acids.

One can determine the percentage of polyunsaturated fatty acids by firstdetermining the amount of polyunsaturated fatty acids in thetriglyceride vegetable oil and then determining the projected finaliodine number by the following formula: ##EQU1## W_(i) is the weightpercentage of the ith fatty acid and n is the total number of saturated,monoenoic and telomerized fatty acids plus the remaining polyunsaturatedfatty acids. This formula determines the projected final iodine numberof a telomerized oil. Iodine number is measured by determining the gramsof iodine absorbed by 100 grams of an oil. For example, iodine number isdetermined by adding 0.5 g of the oil, 10 ml of carbon tetrachloride and25 ml of iodine solution (Wisz Reagent) and incubated for one hour inthe dark at room temperature. After incubation, the reaction is stoppedby addition of 10 ml of 15% (w/w) potassium iodide solution and 100 mlof water. This solution is titrated with 0.10 N sodium thiosulfate untilthe yellow color essentially disappears. At that point, 4 drops of astarch solution is added to form a dark blue color. Titration withsodium thiosulfate continues until the solution exhibits a clear orwhite end product. The iodine number (I) is calculated by the followingequation: ##EQU2##

The iodine number of a triglyceride oil is a combination of the iodinenumber of polyunsaturated (e.g., diunsaturated) components andmonounsaturated components. Prior to the telomerization process, avegetable oil with many polyunsaturated fatty acids will have arelatively high iodine number because a diunsaturated fatty acid reactswith four atoms of iodine (two moles of I₂), whereas a monounsaturatedfatty acid will react with two atoms of iodine (one mole of I₂). Astelomerization proceeds, diunsaturated fatty acids form aliphatic ringstructures with other diunsaturated fatty acids and are converted tosaturated or monounsaturated components. Thus, the iodine numberdecreases because the number of double bonds decreases. At completion oftelomerization, the iodine number becomes the same as that of amonounsaturated triglyceride oil.

For example, if the starting triglyceride vegetable oil had an iodinenumber of 110 and it contained a mixture of trioleylglyceride andtrilinoleylglyceride, the projected completion of telomerization yieldsan iodine number of about 72, because the iodine number oftrioleylglyceride is about 82. The iodine number of trilinoleylglycerideis about 174. Thus, the original triglyceride vegetable oil mixture musthave contained about 30% trilinoleylglyceride and 70% trioleylglyceride.The sum of 70% of 82 plus 30% of 174 is about 110, or the iodine numberof the starting triglyceride vegetable oil.

Another method for monitoring the telomerization process is to determinethe viscosity of the telomerized oil at a particular temperature.Viscosity increases as the triglycerides polymerize and molecular weightincreases. Therefore it is also possible to monitor viscosity at aparticular temperature to determine when the telomerization reaction hasproduced less than 4% polyunsaturated fatty acids because therelationship between viscosity, molecular weight and amount ofpolyunsaturated fatty acids remaining after formation of aliphatic ringsis proportional. The telomerization reaction is complete when viscosityversus time plateaus or increases at a lower rate.

Corn, crambe, meadowfoam, peanut, rapeseed and soybean oils weretelomerized at 300° C. for 7.5 hours as described herein. Viscosity at40° C. for each oil was compared before and after telomerization. Thefollowing Table 7 shows the results.

                  TABLE 7                                                         ______________________________________                                        Viscosity at 40° C. in cs                                              Vegetable Oil Triglyceride                                                                             Telomerized                                          ______________________________________                                        Corn          34         2365                                                 Crambe        49         103                                                  Meadowfoam    54         63                                                   Peanut        36         33                                                   Rapeseed      44         259                                                  Soybean       29         44                                                   ______________________________________                                    

Moreover, as the fatty acids telomerize through formation of aliphaticrings, the molecular weight of the telomerized vegetable increase to amolecular weight of about 2000 to about 5000 daltons.

Aliphatic ring structures, such as cyclohexane rings, have a higherrefractive index than linear compounds of the same molecular weight.Thus an increase in refractive index indicates the formation ofaliphatic rings and telomerization of the vegetable oil. Table 8illustrates oils before and after telomerization at 300° C. for 7.5hours.

                  TABLE 8                                                         ______________________________________                                        Refractive Index                                                              Vegetable Oil Triglyceride                                                                             Telomerized                                          ______________________________________                                        Corn          1.4765     1.4776                                               Crambe        1.4734     1.4742                                               Meadowfoam    1.4735     1.4737                                               Peanut        1.4721     1.4725                                               Rapeseed      1.4740     1.4742                                               Safflower     1.4785     1.4794                                               Soybean       1.4766     1.4770                                               ______________________________________                                    

Addition of a telomerized vegetable oil, according to the presentinvention, can function as a thickening agent for thickening andcross-grading lubricating oils, and particularly for sheer stablederivatives. Thus, a telomerized vegetable oil can function as a lowmolecular weight polymer with additional thermal oxidative stabilitycharacteristics. We added 2%, 4%, and 8% telomerized rapeseed oil to abase fluid having a 79% VI (viscosity index). As shown in Table 9,addition of telomerized rapeseed oil improved viscosity of a low VI oil.

                  TABLE 9                                                         ______________________________________                                                    Base  2%       4%       8%                                                    Fluid Telomer  Telomer  Telomer                                   ______________________________________                                        Viscosity (cs @ 40° C.)                                                              21.37   21.67    21.98  22.62                                   Viscosity (cs @ 100° C.)                                                             4.03    4.26     4.51   5.02                                    Viscosity Index                                                                             79      98       117    116                                     ______________________________________                                    

The telomerization process is conducted in a non-oxidizing atmosphere.Preferably it is conducted with a minimum amount of oxygen present, andmost preferably under a nitrogen blanket. Other reducing atmospheres canbe used, such as the inert gases helium, neon, argon and combinationsthereof.

Preferably, a catalyst at a concentration from about 0.5% to about 5.0%by weight, is added to the triglyceride vegetable oil for thetelomerization reaction. The catalyst is a cationic catalyst, anioniccatalyst, solid strong acid catalyst or a combination thereof. Examplesof cationic catalysts include ester-complexed chloride, phenol-complexedboron trifluoride and dibutyl tin dichloride. Anionic catalysts include,for example, butyl-lithium, butyl potassium, and metallic sodium.Examples of solid acid catalysts include Zeolites and resin sulfonicacid.

Preferably, a reaction initiator may be added to the vegetable oil tostart the telomerization process. An example of a reaction initiator isa peroxide, such as di-t-butyl-peroxide or air, at concentrationsranging from about 1.0% to about 10% by weight.

Vegetable oil for the telomerization process is a triglyceride vegetableoil comprising from about 10% to about 80% polyunsaturated fatty acids.At least 90% of the fatty acids should be from about 16 to about 26carbon atoms in length with few, if any, branched chains. Preferably,the triglyceride vegetable oil contains from about 18 to about 22 carbonatoms in 90% of its fatty acids and from about 10% to about 25% of itsfatty acids are polyunsaturated. Preferred vegetable oils that have thisamount of polyunsaturated fatty acids are rapeseed oil, crambe oil, andmeadowfoam oil. Other appropriate vegetable oils include, for example,soya bean oil, peanut oil, safflower oil, sunflower seed oil, cottonseed oil, olive oil, corn oil, coconut oil, palm oil, combinationsthereof and the like.

Telomerized vegetable oil is further characterized by increasedoxidation resistance. Increased oxidation resistance, or oxidativestability, results from polymerization of the vegetable oils. There arefewer carbon-carbon double bonds in telomerized vegetable oil subject toattack by oxygen. For example, when refined rapeseed oil (iodine number114) was compared with telomerized rapeseed oil (iodine number 82) forthermal oxidative stability, viscosity increase due to oxidation damagewas only 25% for the telomerized oil versus 67% for the triglyceriderapeseed vegetable oil. Each oil was heated to 121° C. and injected with50cc/min of air over a period of 24 hours. These data indicate that theoxidative resistance of the telomerized oil is significantly increasedover the same oil prior to telomerization.

Another oxidative stability comparison was made with rapeseed oil,telomerized rapeseed oil, jojoba oil (a natural wax ester) and severalsynthetic commercial wax esters, often derived from rapeseed oil.Viscosity at 100° C. was compared before air injection and after 24hours of air injection as described above. The following Table 10describes the results:

                  TABLE 10                                                        ______________________________________                                        Sample (Iodine No.)                                                                       Viscosity (0)                                                                            Viscosity (24)                                                                           % Change                                    ______________________________________                                        rapeseed oil (114)                                                                        10.93 cps  18.22 cps  66.7                                        telomerized (82)                                                                          18.64 cps  23.38 cps  25.4                                        jojoba oil (82)                                                                           6.05 cps   8.52 cps   40.8                                        SWEA        5.83 cps   8.43 cps   44.6                                        SWEB        6.00 cps   7.96 cps   32.7                                        SWEC        4.69 cps   6.43 cps   37.1                                        ______________________________________                                    

SWEA, SWEB, and SWEC are liquid synthetic wax esters of rapeseed oil.These data show increased oxidative resistance as a result of thetelomerization process.

Telomerized vegetable oil can be used as part of a lubricant additivealone, and derivatives can be made from telomerized vegetable oil,including phosphite adducts and sulfurized telomerized vegetable oils.Sulfurized derivatives of telomerized vegetable oils are made by knowntechniques of sulfurization. For example, 20 grams of telomerizedrapeseed oil, as described herein, was sulfurized with 1 gram of sulfurat 180° C. for two hours under nitrogen with stirring. The resultingsulfurized telomerized rapeseed oil was soluble at a 5% concentration inmineral oil and had a 2B score in a copper strip test. Similarly, 20grams of telomerized meadowfoam oil was sulfurized with 3 grams ofsulfur under the same conditions. The resulting sulfurized oil wassoluble in mineral oil at a 5% concentration and provided a score of 2Ain the copper strip test.

A phosphite adduct of a telomerized vegetable oil is formed by thereaction product of a telomerized vegetable oil and a compound of theformula: ##STR2## wherein R is H, C₁₋₁₂ alkyl, C₁₋₁₂ aryl, C₁₋₁₂alkaryl, C₁₋₁₂ aralkyl, or cyclo C₄₋₈ alkyl. Preferably, R is C₄₋₈alkyl, C₄₋₈ aryl, C₄₋₈ alkaryl, C₄₋₈ aralkyl, or cyclo C₄₋₈ alkyl. Mostpreferably, R is n-butyl. Telomerized vegetable oils do not have as manyavailable carbon-carbon double bonds as triglyceride vegetable oils. Asthe phosphorous compound attaches to a carbon-carbon double bond, not asmuch phosphorous can be reacted to a telomerized oil as compared withits triglyceride vegetable oil counterpart. Accordingly, it is withinthe scope of the present invention to add a phosphite adduct of anatural wax ester (e.g., jojoba oil) as described in U.S. Pat. No.4,873,008, and/or a phosphite adduct of a synthetic wax ester ortriglyceride oil as described in U.S. Pat. No. 4,970,010.

The present invention further relates to lubricating compositions,comprising a lubricant additive and a lubricant base, (e.g., mineraloil) appropriate for its intended use. Examples of lubricant basesinclude hydrocarbon oil, synthetic hydrocarbon, mineral oil, anester-base, a mixture of mineral oil and an ester base, a mineraloil-based grease, petroleum HVI, MVI and LVI, and a synthetichydrocarbon-based grease. Specific examples can be found in standardtext books and in, for example, U. S. Pat. No. 4,873,008.

Depending upon the application and the desired extent of antiwearprotection, the total lubricant additive concentration within thelubricating composition will be from about 0.1% to about 60% by weight.The lubricant additive of the present invention comprises at least atelomerized vegetable oil and possibly a sulfurized derivative or aphosphite adduct of a triglyceride vegetable oil, a vegetable oil waxester or a telomerized vegetable oil. The lubricant additive comprisesat least one telomerized component from the three groups of components,wherein the three components are telomerized vegetable oil, telomerizedand sulfurized vegetable oil or a sulfurized wax ester, and phosphiteadduct of telomerized vegetable oil. Preferably, a lubricant additivecomprises telomerized vegetable oil, a telomerized and sulfurizedvegetable oil, and a phosphite adduct of a wax ester.

The amount of telomerized component in the lubricant additive will varydepending on the extent of antiwear protection desired and the desiredviscosity of the final lubricating composition. More telomerizedvegetable oil will be substituted for a wax ester or a triglyceridevegetable oil if greater viscosity is needed and more cost savings areneeded. Moreover, sulfurized wax ester will be used in more viscouslubricating compositions, such as greases and hydraulic oils which willalso contain a relatively higher concentration of telomerized vegetableoil. Moreover, a cutting oil or a metal working lubricant will comprisea telomerized vegetable oil, a sulfurized wax ester and a phosphiteadduct of either a telomerized vegetable oil, a vegetable oil, or asynthetic wax ester.

Different combinations and concentrations of the lubricant additive willdepend upon the desired product attributes. For example, a hydraulic oilwill have a lubricant additive comprising (percentages are by weight ofthe total composition) a relatively low concentration (about 0.1% toabout 0.5%) of a sulfurized wax ester, a relatively high concentrationof telomerized vegetable oil (from about 2% to about 5%), and arelatively low concentration of a phosphite adduct of a wax ester or atelomerized vegetable oil (from about 0.1% to about 0.6%). A metalcutting oil, for example, will have a lubricant additive comprisingapproximately 7% sulfurized wax ester, about 1% to about 4% telomerizedvegetable oil and very little, if any, phosphite adduct of a wax esteror a telomerized vegetable oil. An automobile engine oil, for example,will contain a lubricant additive comprising approximately 1% sulfurizedwax ester, approximately 2% telomerized vegetable oil, and approximately2% of a phosphite adduct of a telomerized vegetable oil and/or a waxester, and other additives as are normally used in an automobile engineoil.

The following examples illustrate the frictional characteristics of aparticular telomerized vegetable oil derivative compared with standardlubricant additives. These examples illustrate the properties ofinventive compositions and do not limit the scope of the presentinvention.

EXAMPLE 1

This example illustrates a comparison of coefficient of friction using alow viscosity friction apparatus (LVFA). Three dibutyl phosphite adductoil derivatives were tested, including (a) a triglyceride rapeseed oil,(b) a wax ester of rapeseed oil, and (c) a telomerized rapeseed oil asthe inventive derivative. Each of the three oils was reacted with equalamounts of dibutyl phosphorous as described herein. One percent or twopercent (by weight) phosphite adduct was added to 338 base stock to formeach of the test lubricating compositions. The 338 base stock is asolvent refined mineral oil. The LVFA test was conducted at two slidingspeeds, 5 feet per minute and 15 feet per minute, at a temperature of250° F., pressure of 240 psi, and SAE 1020 steel on steel. The resultsare as follows:

    ______________________________________                                        Composition (phospite adduct)                                                                  Average speed                                                                             % Reduction                                      ______________________________________                                        Sliding Speed 5 Ft/Min Coefficient of Friction                                Base fluid control                                                                             0.0805                                                                        0.0801                                                                        0.0800                                                       Base + 1% ester  0.0695      14                                               Base + 2% ester  0.0645      21                                               Base + 1% triglyceride                                                                         0.0732       9                                               Base + 2% triglyceride                                                                         0.0698      13                                               Base + 1% telomerized                                                                          0.0726      10                                               Base + 2% telomerized                                                                          0.0699      13                                               ______________________________________                                        Sliding Speed 15 Ft/Min Coefficient of Friction                               Base fluid control                                                                             0.0842                                                                        0.0823                                                                        0.0855                                                       Base + 1% ester  0.0724      14                                               Base + 2% ester  0.0671      20                                               Base + 1% triglyceride                                                                         0.0752       9                                               Base + 2% triglyceride                                                                         0.0728      12                                               Base + 1% telomerized                                                                          0.0778       9                                               Base + 2% telomerized                                                                          0.0752      12                                               ______________________________________                                    

These data show that the frictional properties of the dibutyl phosphiteadduct of telomerized vegetable oil are similar to the dibutyl phosphiteadduct of triglyceride vegetable oil. However, the dibutyl phosphiteadduct of a wax ester of vegetable oil displayed somewhat betterfrictional properties.

EXAMPLE 2

This example illustrates a comparison of limited slip additiveformulations in a testing model to measure chatter in a SRD Wheel RollerTest in a Pontiac TransAm Rear Axle. Three limited slip additives wereprepared and added to a Texaco 80W-90 base fluid. The Texaco 80W-90 basefluid is a reference point that provides chatter in a 1982 PontiacTransAm rear axle.

Testing procedure involved: (1) removing differential internalcomponents in a 1982 Pontiac TransAm; (2) reassembling differential withTexaco 80W-90 base fluid; (3) flushing rear axle housing and componentsand installing differential; (4) filling sump with base fluid; (5)driving at least 20 miles for breaking in rear axle; (6) performing aleft and right rear wheel roller for 2-4 min. to determine dynamicthrust; (7) adding a limited slip additive to rear axle sump; (8)driving five miles to circulate the additive; (9) determining left andright well dynamic thrust; (9) elevating sump temperature to 250° F. onwheel rollers to evaluate chatter; and (10) raising the sump temperaturehigher if no chatter was heard at 250° F. Approximately 4 oz. of eachtest limited slip additive was added to the test system differential.

Test formulation 1 comprised (all percentages are by weight) 60% of aN-dibutyl phosphite adduct of a rapeseed oil synthetic wax ester, 10% ofa rapeseed oil wax ester, and 30% polyalpha olefin (4cs viscosity). Testformulation 2 comprised 60% of a N-dibutyl phosphite adduct oftelomerized rapeseed oil (2 moles phosphite adduct added to 1 mole oftelomer), 30% polyalpha olefin (4 cs viscosity) and 10% telomerizedrapeseed oil. Test formulation 3 comprised 60% of a N-dibutyl phosphiteadduct of a rapeseed oil synthetic wax ester, 10% of a rapeseed oilsynthetic wax ester and 30% of petroleum HVI (high viscosity index)neutral oil (about 500 VI).

Only test formulation 2, containing a telomerized oil and a telomerizedderivative, failed to produce chatter the under severe testingconditions. The following Table 10 illustrates this comparison:

                  TABLE 11                                                        ______________________________________                                        Test                                                                          Formulation                                                                            Chatter Rating    Bias Reduction %                                   ______________________________________                                        1        Chatter 8 @ 250° F. sump                                                                 29%                                                2        No chatter @ 280° F. sump                                                                13%/19%                                            3        Chatter 7/8 @ 250° F. sump                                                               23%/27%                                            ______________________________________                                    

A limited slip additive made with telomerized oils, according to thepresent invention, eliminated a chatter problem in a rear axle testsystem that could not be addressed by conventional limited slipadditives.

What is claimed is:
 1. A telomerized triglyceride comprising no morethan 4% polyunsaturated fatty acids and a plurality of aliphatic rings.2. The telomerized vegetable oil of claim 1 wherein the source oftriglyceride vegetable oil is selected from the group consisting ofrapeseed oil, crambe oil, meadowfoam oil, soya bean oil, peanut oil,corn oil, safflower oil, sunflower seed oil, cottonseed oil, olive oil,coconut oil, palm oil, linseed oil, and combinations thereof.
 3. Thetelomerized vegetable oil of claim 1 wherein the source of triglyceridevegetable oil is characterized by having at least 90% of its fatty acidsfrom about 16 to about 26 carbon atoms in length, and having from about10% to about 75% of the fatty acids as polyunsaturated.
 4. Thetelomerized vegetable oil of claim 3 wherein the source of thetriglyceride vegetable oil comprises fatty acids that are from about 18to about 22 carbon atoms in length and having from about 15% to about50% of the fatty acids as polyunsaturated fatty acids.
 5. Thetelomerized vegetable oil of claim 4 wherein the source of thetriglyceride vegetable oil is selected from the group consisting ofrapeseed oil, crambe oil, meadowfoam oil, corn oil, and combinationsthereof.
 6. A lubricant additive comprising a telomerized vegetable oilaccording to claim
 1. 7. A telomerized vegetable oil produced by aprocess comprising heating a triglyceride vegetable oil in anon-oxidizing atmosphere in the presence of water vapor for at least 5hours at a temperature from about 200° C. to about 400° C. or heatingunder sufficient heat and time conditions to lower the number ofpolyunsaturated fatty acids to less than 4% of the total number of fattyacids through the formation of aliphatic rings, wherein saidtriglyceride vegetable oil has from about 10% to about 75% of its fattyacids being polyunsaturated and having from about 16 to about 26 carbonatom chain lengths.
 8. The telomerized vegetable oil of claim 7 whereinthe triglyceride vegetable oil is selected from the group consisting ofrapeseed oil, crambe oil, meadowfoam oil, soya bean oil, peanut oil,corn oil, safflower oil, sunflower seed oil, cottonseed oil, olive oil,coconut oil, palm oil, linseed oil, and combinations thereof.
 9. Thetelomerized vegetable oil of claim 7 further comprising adding acatalyst to the triglyceride vegetable oil, wherein the catalyst isselected from the group consisting of cationic catalysts, anioniccatalysts, solid acid catalysts, reaction initiators, and combinationsthereof.
 10. The telomerized vegetable oil of claim 7 wherein thenon-oxidizing atmosphere comprises nitrogen.
 11. A process fortelomerizing a triglyceride vegetable oil comprising heating atriglyceride vegetable oil in a non-oxidizing atmosphere in the presenceof water vapor for at least 5 hours at a temperature from about 200° C.to about 400° C. or heating under sufficient heat and time conditions tolower the number of polyunsaturated fatty acids to less than 4% of thetotal number of fatty acids through the formation of aliphatic rings,wherein said triglyceride vegetable oil having from about 10% to about75% of its fatty acids being polyunsaturated and having from about 16 toabout 26 carbon atom chain lengths.
 12. The process of claim 11 whereinthe triglyceride vegetable oil is selected from the group consisting ofrapeseed oil, crambe oil, meadowfoam oil, soya bean oil, peanut oil,corn oil, safflower oil, sunflower seed oil, cottonseed oil, olive oil,coconut oil, palm oil, linseed oil, and combination thereof.
 13. Theprocess 11 further comprising adding a catalyst to the triglyceridevegetable oil, wherein the catalyst is selected from the groupconsisting of cationic catalysts, anionic catalysts, solid acidcatalysts, reaction initiators, and combinations thereof.
 14. Theprocess of claim 11 wherein the non-oxidizing atmosphere comprisesnitrogen.